I'd beg to differ Isotronics, Hiding is a big part of security, because what you can't see you can't attack. A real life example of this is in the Army...they have Bullet proof armour available..that dosn't mean that can walk around in bright pink Uniforms..
If hiding isn't important then why do Firewalls now incorperate Stealth technology? Not responding to Ping's is a way of hiding, but your partialy right, hiding isn't every thing...you still need to harden your system.

As for the question in this thread, I don't think you can hide your IP very effectivly on IRC because of the Servers checking for Proxies, how ever, you can harden your system...that way you shouldn't really be needing to hide....

just my 2 cents...

- Noia